cycles vector blur different with camera motion
Closed, ResolvedPublic


In the attached file there is camera motion that produces very different vector blur to blender internal.

Test the bug by opening the attached file and pressing render on both render layers one after another.

Then you can ctrl+click on each render layer to see the difference.

attached *_lite.jpg showing the error.

also attached a more extreme example from one of the mango production files.



Looked into this issue. It seems that Cycles in fact behaves more predictable here. There're issues like large ground plane which goes beyong the camera which mustn't happen when using Blender Internal renderer. Subdividing it should make results closer to each other.
Looking further into this issue, because in some cases speed used as an input for vector blur doesn't behave as it's expected.

I would say that final verdict would be cycles vector pass works good enough. In same cases it's indeed different from blender internal, but that's just because of wrong setup of the scene.
It was indeed an issue with vector pass in cases when first render layer didn't have vector pass enabled which was fixed in tomato branch. Would check on if it's possible to make that fix more elegant, but that's not something which should stay in bug tracker.

I believe this report could be closed until netx buggy setup would be discovered.

Sergey Sharybin (sergey) closed this task as Resolved.Aug 5 2012, 10:26 PM